The invention relates to a camshaft, as well as to a method for producing a camshaft.
Camshafts for the control of internal combustion engines for motor vehicles are today installed in ever more compact configurations. For example, for reasons of saving space, camshafts are disposed pairwise in such proximity that direct access to the cylinder head bolts is no longer possible. In order to dismount the cylinder head or to tighten up cylinder head bolts, such camshafts must in these cases be first dismounted, which is not service-friendly and entails additional costs. In the case of solidly built-up camshafts one solution proposes to mill or grind a transversely disposed groove-shaped indentation in the proximity of the cylinder head bolts. It is also possible in the case of solidly cast camshafts to cast the indentations directly. In order to establish access to the cylinder head bolts, the camshafts can be rotated in this case such that the camshaft indentations expose the region of the cylinder head bolts.
However, for purposes of simplification and to save expenses, for some time camshafts have no longer been produced, such as cast, of one part, but rather are produced as so-called built-up camshafts, i.e. they are assembled from several parts. Such a built-up camshaft comprises a tube, onto which prefabricated cams are slid up to their position and fixed on the tube. In such a camshaft tube it is not possible to apply indentations in the known manner, for example by milling. Milling would weaken the camshaft tube in the proximity of the indentations to such an extent that the loading would not be tolerable during engine operation. If, for reinforcement of the milled-out indentations in the camshaft tube, a further tube or even a full shaft were to be pressed into the same, sufficient strength would still not be ensured in many cases and would reduce the weight advantages of built-up hollow camshafts, if not even completely negate them, and would cause additional costs.